The Effect of Au and Rh Nanoclusters on Methanol Decomposition on CuO/Cu(110)

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/92530

Title:	The Effect of Au and Rh Nanoclusters on Methanol Decomposition on CuO/Cu(110)
Authors:	劉冠辰;Liu, Guan-Chen
Contributors:	物理學系
Keywords:	氧化銅;銅(110)單晶;金屬納米糰簇;甲醇分解;Copper Oxides;Cu(110);Metal Nanoclusters;Methanol Decomposition
Date:	2023-04-19
Issue Date:	2024-09-19 15:54:56 (UTC+8)
Publisher:	國立中央大學
Abstract:	經由蒸鍍生長在氧化銅上的金(Au)和銠(Rh)奈米粒子增加生長在Cu(110)單晶上的氧化銅薄膜對甲醇分解的活性。氧化銅薄膜有(2×1)氧化相和(2×1)和c(6×2)共存相兩種氧化銅相，分別由將Cu(110)曝露於7 – 40 L和1000 L的氧氣生成。氧化銅薄膜的結構由低能電子繞射(LEED)來監控，反應產物則是由熱脫附質譜(TPD)和光電子能譜(PES)來偵測。在超高真空環境下，甲醇-d4 (CD3OD)在氧化銅薄膜上分解產生甲醛-d2 (CD2O)、氘分子(D2)和重水(D2O)。金和銠奈米粒子在氧化銅上增加甲醇分解的機率。銠奈米粒子促進一氧化碳的產生。除此之外，甲醛和水的產量隨著金和銠的覆蓋率增加而上升，相反地，氘分子的產量則是下降。氘分子產量下降是由氫原子和羥基(OD-)結合產生水導致。而且，在(2×1)氧化相和(2×1)和c(6×2)共存相兩種氧化銅薄膜上的金和銠奈米粒子對產量的增長百分比不同。最小的0.05 ML金和銠奈米粒子或單原子不會增加甲醇在由7 L 和 1000 L曝氧量生成的氧化銅薄膜上的分解。特別是，0.05 ML的Rh小顆奈米粒子或是單原子在(2×1)和c(6×2)共存相的氧化銅上阻擋甲醇的分解。這由產量的降低並且甲醇的吸附量沒有減少來證明。 ;The reactivity of copper oxide films grown on Cu(110) single crystal (CuO/Cu(110)) toward methanol decomposition was shown to be enhanced by gold (Au) and Rhodium (Rh) nanoclusters formed by vapor deposition onto the copper oxide films. Two kinds of copper oxide phase were observed on the surface; (2×1) oxide phase and (2×1) and c(6×2) coexistence phase was yielded by exposing Cu(110) to 7 – 40 L and 1000 L of oxygen, respectively. The structures of the copper oxide films were characterized with low electron energy diffraction (LEED), and the reaction products were monitored with temperature programmed desorption (TPD) and synchrotron-based photoelectron spectroscopy (PES). Decomposition of methanol-d4 (CD3OD) on CuO/Cu(110) produced formaldehyde-d2 (CD2O), molecular deuterium (D2) and deuterium water (D2O) under UHV conditions. Au and Rh nanoclusters supported on copper oxide films increased the probability of methanol decomposition. Rh nanoclusters facilitate the production of CO. Besides, the production of formaldehyde-d2 and deuterium water was increased with Au and Rh coverage, in contrast, that of deuterium molecules was reduced. The decrease in deuterium production resulted from the combination of deuterium molecules with hydroxyls (OD^-) to produce deuterium water. Moreover, copper oxide films formed with (2×1) oxide phase and (2×1) and c(6×2) coexistence phase showed different increased production after Au and Rh deposition. The smallest Au and Rh nanoclusters (0.05 ML) nanoclusters, or single atoms, didn’t enhance methanol decomposition on copper oxide films formed by 7 and 1000 L of oxygen exposure. In particular, 0.05 ML Rh small nanoclusters, or single atoms, supported on copper oxide films with (2×1) and c(6×2) coexistence phase blocked the methanol decomposition. This was evidenced by the lower production and no decrease in the number of monolayer adsorbed methanol.
Appears in Collections:	[Graduate Institute of Physics] Electronic Thesis & Dissertation

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